邮件发送失败！异常原因：The message was undeliverable. All servers failed to receive the message

邮件发送失败！错误原因：The message was undeliverable. All servers failed to receive the message
on   error   resume   next
body= "66666s "
MailServerUserName= "dfboyxing@126.com "
MailServerPassword= "111111 "
mailaddress= "dfboyxing@sina.com "

mailtopic= "你好 "
body=Request.Form( "Mailbody ")
smtpmail= "dfboyxing@126.com "
smtp= "smtp.126.com "

Set   JMail=Server.CreateObject( "JMail.Message ")
JMail.Charset= "gb2312 "
jmail.ContentType   =   "text/html "
JMail.AddRecipient   mailaddress
JMail.Subject   =   mailtopic
JMail.Body   =   body
JMail.From   =   smtpmail
JMail.MailServerUserName   =   MailServerUserName
JMail.MailServerPassword   =   MailServerPassword
JMail.Send   smtp
Set   JMail=nothing


If   Err   Then

Response.Write   "邮件发送失败！错误原因： "   &   Err.Description   &   " <br> "

else
.......


怎么测试都提示这个错误
邮件发送失败！错误原因：The   message   was   undeliverable.   All   servers   failed   to   receive   the   message
兄弟们帮帮忙啊,弄了一上午了.

------解决方案--------------------
如果系统是win2003的话，比较麻烦，因为在win2000里面，jmail 发送邮件的进程是 dllhost.exe 在win2003里面发送邮件进程是 w3wp.exe，所以在杀毒软件要设置允许w3wp.exe 这个进程发邮件